U.S. patent application number 12/369805 was filed with the patent office on 2009-08-20 for display device and manufacturing method thereof.
This patent application is currently assigned to Hitachi Displays, Ltd.. Invention is credited to Noriharu Matsudate, Takeshi Ookawara.
Application Number | 20090206749 12/369805 |
Document ID | / |
Family ID | 40954476 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090206749 |
Kind Code |
A1 |
Matsudate; Noriharu ; et
al. |
August 20, 2009 |
DISPLAY DEVICE AND MANUFACTURING METHOD THEREOF
Abstract
A display device includes plural pixels each including a pixel
electrode and a transparent electrode formed above the pixel
electrode and an auxiliary wiring formed between light emitting
regions each in each of the pixels on the transparent electrode, in
which the auxiliary wiring is a metal wiring in a stripe shape
formed on a resin. The transparent electrode is formed in common
with each of the pixels, and a sheet resistance obtained by
combining the transparent electrode with the metal wiring is 10
.OMEGA./.quadrature. or less. The metal wiring is Cu, Al or SUS. A
blackening treatment is applied to the metal wiring. The
transparent electrode is ITO, IZO or ZnO. The metal wiring is
formed in a non-light emitting region between the light emitting
regions in each of the pixels in an extending direction of a
scanning line. The resin is PET, TAC or POC.
Inventors: |
Matsudate; Noriharu;
(Kujukuri, JP) ; Ookawara; Takeshi; (Mobara,
JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Assignee: |
Hitachi Displays, Ltd.
|
Family ID: |
40954476 |
Appl. No.: |
12/369805 |
Filed: |
February 12, 2009 |
Current U.S.
Class: |
313/505 ;
445/46 |
Current CPC
Class: |
H01L 51/5234 20130101;
H01L 2251/5315 20130101; H01L 27/3246 20130101 |
Class at
Publication: |
313/505 ;
445/46 |
International
Class: |
H01J 1/53 20060101
H01J001/53; H01J 9/02 20060101 H01J009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2008 |
JP |
2008-032502 |
Claims
1. A display device comprising: a plurality of pixels each
including a pixel electrode and a transparent electrode formed
above the pixel electrode; and an auxiliary wiring formed between
light emitting regions each in each of the pixels on the
transparent electrode, wherein the auxiliary wiring is a metal
wiring in a stripe shape formed on a resin.
2. The display device according to claim 1, wherein the transparent
electrode is formed in common with each of the pixels, and a sheet
resistance obtained by combining the transparent electrode with the
metal wiring is 10 .OMEGA./.quadrature. or less.
3. The display device according to claim 1, wherein the metal
wiring is Cu, Al or SUS.
4. The display device according to claim 1, wherein a blackening
treatment is applied to the metal wiring.
5. The display device according to claim 1, wherein the transparent
electrode is ITO, IZO or ZnO.
6. The display device according to claim 1, further comprising a
scanning line which inputs a scanning voltage to each of the
pixels, wherein the metal wiring is formed in a non-light emitting
region between the light emitting regions each in each of the
pixels in an extending direction of the scanning line.
7. The display device according to claim 1, further comprising a
separation wall which separates each of the pixels, wherein the
light emitting region in each of the pixels is separated by the
separation wall for each of the pixels, and the metal wiring is
formed above the transparent electrode above the separation
wall.
8. The display device according to claim 1, wherein the resin is
PET, TAC or POC.
9. A method of manufacturing a display device including: a
plurality of pixels each having a pixel electrode and a transparent
electrode formed above the pixel electrode; and an auxiliary wiring
formed between light emitting regions each in each of the pixels on
the transparent electrode, the method comprising the steps of:
preparing a resin having a metal wiring formed in a stripe shape on
a main surface thereof; forming the pixel electrode above a
substrate; forming the transparent electrode above the pixel
electrode; and bonding the prepared resin on the transparent
electrode such that the main surface faces the transparent
electrode to form the auxiliary wiring between the light emitting
regions each in each of the pixels on the transparent
electrode.
10. The method of manufacturing a display device according to claim
9, wherein the step of preparing the resin having the metal wiring
formed in a stripe shape on the main surface thereof includes the
step of forming a metal material on the main surface of the resin,
and the step of etching the metal material by photo etching to form
the metal wiring in a stripe shape.
11. The method of manufacturing a display device according to claim
9, wherein the step of preparing the resin having the metal wiring
formed in a stripe shape on the main surface thereof is the step of
forming the metal wiring in a stripe shape on the main surface of
the resin by a printing method or a deposition method.
12. The method of manufacturing a display device according to claim
9, further comprising the step of forming a separation wall which
separates the light emitting region in each of the pixels after the
step of forming the pixel electrode above the substrate, wherein
the step of forming the transparent electrode above the pixel
electrode is the step of forming the transparent electrode so as to
cover the separation wall in common with each of the pixels.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority from Japanese
Application JP 2008-32502 filed on Feb. 14, 2008, the content of
which is hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a display device and a
manufacturing method thereof and more particularly to a forming
method of an auxiliary wiring in an organic electroluminescent
display device.
[0004] 2. Description of the Related Art
[0005] In a top emission type organic electroluminescent display
device, since a pixel portion can be designed above a thin film
transistor used for driving a pixel (hereinafter referred to as
"drive TFT") or a wiring, and therefore there is no influence of
the area of the drive TFT or wiring, a pixel aperture ratio can be
increased. Therefore, the top emission type organic
electroluminescent display device has such an advantage that the
higher resolution or higher luminance of the organic
electroluminescent display panel can be achieved, or that power
consumption can be reduced.
[0006] However, it involves problems that a metal oxide such as ITO
or IZO must be used for an upper transparent electrode (common
electrode) present in a light extraction direction, and also that
the electric resistance of the metal oxide is higher than that of a
metal such as Al (aluminum). That is, because of the high
resistance of the upper transparent electrode, voltage drop occurs
at the center and periphery of the screen of the organic
electroluminescent display panel. Therefore, it is difficult to
ensure the uniformity of luminance.
[0007] In order to reduce the resistance of the upper transparent
electrode, a method has been adopted in which a metal of low
resistance, such as Al, is finely wired above or below the upper
transparent electrode and connected to the transparent electrode,
whereby the electric resistance of the upper transparent electrode
is reduced as a whole (refer to Patent Documents 1 to 3, listed
below).
[0008] Related art documents relating to the invention of the
present application are as follows.
[0009] Patent Document 1: JP-A-2007-103058
[0010] Patent Document 2: JP-A-2007-103098
[0011] Patent Document 3: JP-A-2007-108469
SUMMARY OF THE INVENTION
[0012] When the above-described fine metal wiring of low resistance
is defined as an auxiliary wiring, the preparing method of the
auxiliary wiring can be mainly classified into the following two
methods.
[0013] (1) Manufacturing the auxiliary wiring used below a
transparent electrode by photo process
[0014] (2) Preparing a metal of low resistance, such as Al, below
or above a transparent electrode by deposition
[0015] In the former case, a change in the manufacturing process
due to an increase in the number of photo processes and an increase
in cost are inevitable.
[0016] In the latter case, on the other hand, it is easily
conceivable that when the metal of low resistance, such as Al, is
deposited, the damage to an organic electroluminescent element due
to the elevation of temperature of a deposition mask or substrate,
the displacement of the auxiliary wiring due to the degradation of
deposition accuracy, or the like occurs because the metal of low
resistance, such as Al, is a high melting point metal. Further, the
problem of the deterioration in display quality due to the diffused
reflection of external light or the like is also conceivable
because the metal of low resistance, such as Al, has metal
gloss.
[0017] The invention has been made to solve the problems in the
related art, and it is an object of the invention to provide a
technique enabling the formation of an auxiliary wiring on a common
electrode with high accuracy without damaging a light emitting
layer in a display device and a manufacturing method thereof.
[0018] A typical outline of the invention disclosed in the present
application will be described below.
[0019] (1) A display device includes: a plurality of pixels each
including a pixel electrode and a transparent electrode formed
above the pixel electrode; and an auxiliary wiring formed between
light emitting regions each in each of the pixels on the
transparent electrode, in which the auxiliary wiring is a metal
wiring in a stripe shape formed on a resin.
[0020] (2) In (1), the transparent electrode is formed in common
with each of the pixels, and a sheet resistance obtained by
combining the transparent electrode with the metal wiring is 10
.OMEGA./.quadrature. or less.
[0021] (3) In (1) or (2), the metal wiring is Cu, Al or SUS.
[0022] (4) In any of (1) to (3), a blackening treatment is applied
to the metal wiring.
[0023] (5) In any of (1) to (4), the transparent electrode is ITO,
IZO or ZnO.
[0024] (6) In any of (1) to (5), the display device further
includes a scanning line which inputs a scanning voltage to each of
the pixels, in which the metal wiring is formed in a non-light
emitting region between light emitting regions each in each of the
pixels in an extending direction of the scanning line.
[0025] (7) In any of (1) to (6), the display device further
includes a separation wall which separates each of the pixels, in
which the light emitting region in each of the pixels is separated
by the separation wall for each of the pixels, and the metal wiring
is formed above the transparent electrode above the separation
wall.
[0026] (8) In any of (1) to (7), the resin is PET, TAC or POC.
[0027] (9) A method of manufacturing a display device including: a
plurality of pixels each having a pixel electrode and a transparent
electrode formed above the pixel electrode; and an auxiliary wiring
formed between light emitting regions each in each of the pixels on
the transparent electrode, the method includes the steps of:
preparing a resin having a metal wiring formed in a stripe shape on
a main surface thereof; forming the pixel electrode above a
substrate; forming the transparent electrode above the pixel
electrode; and bonding the prepared resin on the transparent
electrode such that the main surface faces the transparent
electrode to form the auxiliary wiring between the light emitting
regions each in each of the pixels on the transparent
electrode.
[0028] (10) In (9), the step of preparing the resin having the
metal wiring formed in a stripe shape on the main surface thereof
includes the step of forming a metal material on the main surface
of the resin, and the step of etching the metal material by photo
etching to form the metal wiring in a stripe shape.
[0029] (11) In (9), the step of preparing the resin having the
metal wiring formed in a stripe shape on the main surface thereof
is the step of forming the metal wiring in a stripe shape on the
main surface of the resin by a printing method or a deposition
method.
[0030] (12) In any of (9) to (11), the method further includes the
step of forming a separation wall which separates the light
emitting region in each of the pixels after the step of forming the
pixel electrode above the substrate, in which the step of forming
the transparent electrode above the pixel electrode is the step of
forming the transparent electrode so as to cover the separation
wall in common with each of the pixels.
[0031] A typical effect obtained by the invention disclosed in the
present application will be briefly described below.
[0032] According to the invention, an auxiliary wiring can be
formed on a common electrode with high accuracy without damaging a
light emitting layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a circuit diagram showing an equivalent circuit of
one pixel (sub-pixel) of an organic electroluminescent display
panel serving as the premise of the invention;
[0034] FIG. 2 is a schematic cross sectional view showing a cross
sectional structure of a main portion of one pixel of the organic
electroluminescent display panel serving as the premise of the
invention;
[0035] FIG. 3 shows an example of a constitution of an organic
electroluminescent element (OLE) shown in FIG. 2;
[0036] FIG. 4 shows an arrangement pattern of an auxiliary wiring
(SUP) shown in FIG. 2;
[0037] FIG. 5 is an explanatory view of an auxiliary wiring
constituting member according to an embodiment of the
invention;
[0038] FIG. 6 is a perspective view showing the auxiliary wiring
constituting member according to the embodiment of the invention in
an enlarged manner;
[0039] FIG. 7 is a schematic cross sectional view showing a state
before bonding the auxiliary wiring constituting member shown in
FIGS. 5 and 6 with an organic electroluminescent display panel not
formed with the auxiliary wiring (SUP) in the structure shown in
FIG. 2;
[0040] FIG. 8 is a schematic cross sectional view showing a state
after bonding the auxiliary wiring constituting member shown in
FIGS. 5 and 6 with the organic electroluminescent display panel not
formed with the auxiliary wiring (SUP) in the structure shown in
FIG. 2;
[0041] FIG. 9 is an explanatory view of a problem caused when the
auxiliary wiring (SUP) is formed on a common electrode (CD) by a
conventional process; and
[0042] FIG. 10 is an explanatory view of a problem caused when the
auxiliary wiring (SUP) is formed below the common electrode (CD) by
the conventional process.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] Hereinafter, an embodiment of the invention will be
described in detail with reference to the drawings.
[0044] Throughout the drawings for explaining the embodiment, the
same reference numerals are assigned to elements having the same
functions, and the repetitive description thereof is omitted.
[0045] In the embodiment, an example in which the invention is
applied to a top emission type active matrix organic
electroluminescent display device will be described.
[Organic Electroluminescent Display Panel Serving as the Premise of
the Invention]
[0046] FIG. 1 is a circuit diagram showing an equivalent circuit of
one pixel (sub-pixel) of an organic electroluminescent display
panel serving as the premise of the invention.
[0047] As shown in FIG. 1, in the organic electroluminescent
display panel serving as the premise of the invention, a video line
(DATA) and a power supply line (POWER) are disposed in the vertical
direction, an auxiliary wiring (SUP) and a scanning line (SCAN) are
disposed in the horizontal direction, and each of pixels is formed
among these wirings.
[0048] Each of the pixels includes a first transistor (TFT1), a
second transistor (TFT2), a data holding capacitor (CAP), and an
organic electroluminescent element (OLE).
[0049] The first transistor (TFT1) is connected to the video line
(DATA) at one end of the source/drain region thereof, connected to
one end of the data holding capacitor (CAP) at the other end of the
source/drain region thereof, and connected to the scanning line
(SCAN) at the gate thereof as a control terminal.
[0050] The end of the data holding capacitor (CAP) is also
connected to the control terminal of the second transistor (TFT2),
and the other end of the data holding capacitor (CAP) is connected
to the power supply line (POWER).
[0051] Not only the data holding capacitor (CAP) but also one end
of the source/drain region of the second transistor (TFT2) is
connected to the power supply line (POWER). The other end of the
source/drain region of the second transistor (TFT2) is connected to
the anode of the organic electroluminescent element (OLE). The
cathode of the organic electroluminescent element (OLE) is
connected to the auxiliary wiring (SUP).
[0052] FIG. 2 shows a cross sectional structure of a main portion
of one pixel of the organic electroluminescent display panel
serving as the premise of the invention.
[0053] As shown in FIG. 2, in the organic electroluminescent
display panel serving as the premise of the invention, a base film
(UC), a semiconductor film (FG), a gate insulating film (GI), a
metal gate electrode film (SG), a first inter-layer insulating film
(INS1), a metal electrode film (ADM), a second inter-layer
insulating film (INS2), a pixel electrode (AD), a bank (BNK), the
auxiliary wiring (SUP), the organic electroluminescent element
(OLE), and a common electrode (CD) are formed above a substrate
(SUB). In FIG. 2, an arrow A shows the irradiation direction of
light emitted from the organic electroluminescent element
(OLE).
[0054] The substrate (SUB) is a non-alkali glass with a thickness
of 0.5 mm.
[0055] The base film (UC) is provided for avoiding the influence of
ionic impurities contained in the substrate (SUB) on a thin film
transistor (TFT) constituting the first transistor (TFT1) or the
second transistor (TFT2) and includes a stacked film of a silicon
nitride film with a thickness of from 50 to 200 nm and a silicon
oxide film with a thickness of from 50 to 200 nm.
[0056] The semiconductor film (FG) is a layer constituting not only
the source region, drain region, and channel region of the thin
film transistor (TFT) which constitutes the first transistor (TFT1)
or the second transistor (TFT2) but also a wiring due to heavy
doping or the lower electrode of the data holding capacitor (CAP).
The semiconductor film (FG) is composed of polysilicon with a
thickness of from 50 to 150 nm.
[0057] The gate insulating film (GI) includes a silicon oxide film
with a thickness of from 100 to 200 nm formed of TEOS, covering the
entire surface of the substrate except for a contact hole. The gate
insulating film (GI) functions not only as a gate insulating film
but also as a dielectric layer of the data holding capacitor
(CAP).
[0058] The metal gate electrode film (SG) serves as the gate
electrode of the first transistor (TFT1) and the gate electrode of
the second transistor (TFT2) as well as is a layer constituting the
upper electrode of the scanning line (SCAN) and the data holding
capacitor (CAP). The metal gate electrode film (SG) is a metal film
with a thickness of from 100 to 300 nm and includes an alloy film
(MoW) of molybdenum (Mo) and tungsten (W).
[0059] The first inter-layer insulating film (INS1) includes a
silicon oxide film with a thickness of from 200 to 500 nm, covering
the entire surface of the substrate except for a contact hole.
[0060] The metal electrode film (ADM) constitutes not only the
video line (DATA) and the power supply line (POWER) but also a
wiring upon connecting the semiconductor film (FG) with the metal
gate electrode film (SG) or a redundant wiring to reduce
resistance. The metal electrode film (ADM) includes a metal film
with a stacked structure having an AlSi film with a thickness of
about from 200 to 400 nm interposed between a MoW film with a
thickness of about from 20 to 120 nm and a MoW film with a
thickness of about from 50 to 150 nm.
[0061] The second inter-layer insulating film (INS2) has a stacked
structure in which an organic insulating film, made of one selected
from polyimide, acrylic, and epoxy, with a thickness of from 1
.mu.m to 2 .mu.m is formed on a silicon nitride film with a
thickness of from 300 to 500 nm, covering the entire surface of the
substrate except for a contact hole.
[0062] The pixel electrode (AD) includes two (upper and lower)
layers. The lower layer includes a stacked film of an AlSi film
with a thickness of from 50 to 200 nm and a MoW film with a
thickness of about from 20 to 120 nm (AlSi film for upper layer and
MoW film for lower layer) and is separated for each pixel. The
upper layer includes an ITO (Indium Tin Oxide) film with a
thickness of about from 30 to 200 nm and is separated for each
pixel. The upper layer ITO covers the lower layer metal and is
electrically connected directly to the second transistor (TFT2) not
by way of the lower layer. That is, the upper layer of the pixel
electrode (AD) functions as an anode for hole injection while the
lower layer functions as a reflective film which reflects light
emitted from the organic electroluminescent element (OLE).
[0063] The bank (BNK) is an insulating film which covers the outer
edge of the pixel electrode (AD) and insulates light emitting
regions (ARA) from each other, the light emitting regions (ARA)
each exposing the pixel electrode (AD), and composed of silicon
nitride (SiN), acrylic, or polyimide.
[0064] As shown in FIG. 3, the organic electroluminescent element
(OLE) includes at least three layers of a hole transport layer 22,
a light emitting layer 21, and an electron transport layer 20. At
least one layer of the organic electroluminescent element (OLE) is
also formed on the bank.
[0065] The common electrode (CD) serving as a cathode includes a
zinc based oxide conductive film such as of IZO, covering the
entire surface of the organic electroluminescent element (OLE).
[0066] The auxiliary wiring (SUP) is formed on the common electrode
(CD). The auxiliary wiring (SUP) is formed in a non-light emitting
region between the light emitting regions (ARA) each in each pixel
in the extending direction of the scanning line (SCAN). That is,
the auxiliary wiring (SUP) is formed on the banks (BNK) extending
from side to side among the banks (BNK) extending from side to side
and up and down. FIG. 4 shows the plane pattern of the auxiliary
wiring (SUP). As shown in FIG. 4, the wiring width of the auxiliary
wiring (SUP) is set to from 10 to 15 .mu.m, and the distance
between the light emitting regions (ARA) each in each pixel is set
to from 25 to 30 .mu.m.
[0067] In this manner, in the top emission type organic
electroluminescent display device, the pixel electrode (AD) and the
organic electroluminescent element (OLE) can be formed above the
first transistor (TFT1), the second transistor (TFT2), and each
wiring. Therefore, the pixel aperture ratio can be increased, so
that the top emission type organic electroluminescent display
device has such an advantage that the higher resolution or higher
luminance of the organic electroluminescent display panel can be
achieved, or that power consumption can be reduced.
[0068] As described above, the auxiliary wiring (SUP) is used for
the purpose of reducing the resistance of the common electrode
(CD). Therefore, a metal having a sufficiently lower electric
resistance than that of ITO, IZO or ZnO which is the material for
the common electrode (CD) must be used for the auxiliary wiring
(SUP). Therefore, Al, which is easily available at present and has
a low electric resistance, and whose film formation method is
stabilized, is used for the auxiliary wiring (SUP).
[0069] In the case of using Al for the material of the auxiliary
wiring, however, the temperature of a deposition source is 1500 K
or more when a usual resistance heating or induction heating method
is used because Al is a high melting point metal. Therefore, damage
to the organic electroluminescent element (OLE) or the like becomes
a problem due to the elevation of temperature of a high-resolution
deposition mask or the elevation of temperature of a substrate and
further the contact between a deposition mask heated to a high
temperature and the organic electroluminescent element (OLE). The
damage to the organic electroluminescent element (OLE) is a problem
relating to the reliability of the organic electroluminescent
display panel, for which a sufficient countermeasure must be
taken.
[0070] On the other hand, the influence of the elevation of
temperature of a deposition mask or substrate causes the thermal
expansion of the deposition mask or substrate, leading to a problem
of deposition displacement of a film forming position of the
auxiliary wiring (SUP). The deposition displacement causes display
failure as a product when the displacement exceeds a design margin,
that is, when the auxiliary wiring (SUP) is shifted and deposited
on a pixel. FIG. 9 shows this state schematically.
[0071] When the auxiliary wiring (SUP) is formed below the organic
electroluminescent element (OLE), it is unnecessary to consider the
damage to the organic electroluminescent element (OLE) due to the
elevation of temperature of a high-resolution deposition mask or
the elevation of temperature of a substrate and further the contact
between a deposition mask heated to a high temperature and the
organic electroluminescent element (OLE). Therefore, the patterning
of the auxiliary wiring (SUP) with high accuracy is possible by
photolithography.
[0072] However, when the auxiliary wiring (SUP) is formed below the
organic electroluminescent element (OLE), the organic film
interferes with the connection between the auxiliary wiring (SUP)
and the common electrode (CD) because the organic film is present
therebetween. FIG. 10 shows this state schematically.
[0073] This becomes a problem not only in a color organic
electroluminescent display device in which single color emission is
combined with a color filter but also in an organic
electroluminescent display device adopting the so-called "solid
deposition" in which, even for multicolor emission, at least one
layer constituting a light-emitting material layer is commonly
deposited also for a different color pixel in order to simplify the
process. In FIGS. 9 and 10, the structure between the substrate
(SUB) and the pixel electrode (AD) shown in FIG. 2 is represented
by BTFT, and the illustration of the structure between the
substrate (SUB) and the pixel electrode (AD) shown in FIG. 2 is
omitted.
[Feature of Organic Electroluminescent Display Panel According to
Embodiment of the Invention]
[0074] An organic electroluminescent display panel according to the
embodiment of the invention has a feature of constituting an
auxiliary wiring constituting member with a different part from the
organic electroluminescent display panel and combining the organic
electroluminescent display panel with the auxiliary wiring
constituting member.
[0075] FIG. 5 is an explanatory view of an auxiliary wiring
constituting member according to the embodiment of the invention,
and FIG. 6 is a perspective view showing the auxiliary wiring
constituting member according to the embodiment of the invention in
an enlarged manner.
[0076] The auxiliary wiring constituting member shown in FIGS. 5
and 6 includes a resin film (RESIN) composed of PET (PolyEthylene
Terephthalate) and a metal wiring (MLINE) formed into a stripe
shape on the resin film (RESIN).
[0077] The auxiliary wiring constituting member is prepared by, for
example, bonding a copper foil reduced to a thickness of 10 .mu.m
or less by cold rolling with a PET film by a decorative steel sheet
technique, then etching the copper foil by an etching technique
which jets an etching solution at a high temperature under a high
pressure to fabricate the metal wiring (MLINE) such that the taper
angle thereof is from 80 to 90 degree, and forming the metal wiring
(MLINE) into a stripe shape.
[0078] When this process is used, the metal wiring (MLINE) having a
wiring pitch (PITCH) of from 80 to 1000 .mu.m, a wiring width
(WIDTH) of from 8 to 50 .mu.m, and a wiring height (HEIGHT) of from
10 to 150 .mu.m can be manufactured appropriately.
[0079] Accordingly, when the process is used, a resolution of about
300 LPI (Line per inch) can be sufficiently achieved for the metal
wiring (MLINE). Therefore, the process provides a sufficient
fabrication degree for the purpose of forming the pattern of the
auxiliary wiring (SUP) of the organic electroluminescent display
panel.
[0080] Further, since a metal used for the pattern of the metal
wiring (MLINE) has a wiring thickness of about 10 .mu.m of a plate
thickness, the electric resistance is reduced to about 1/10
compared with that of a metal wiring patterned above a general
glass substrate by photo process and having a thickness of about 1
.mu.m. Therefore, the auxiliary wiring (SUP) according to the
embodiment shows the lowest wiring resistance compared with that
obtained by a conceivable forming process of the auxiliary wiring
under current situation, that is, a photo process method or a
vacuum deposition method.
[0081] In the embodiment, ITO, IZO or ZnO is used as the common
electrode (CD). In the embodiment, when ITO, IZO or ZnO is used as
the common electrode (CD), and the auxiliary wiring constituting
member is combined with the common electrode (CD) of the organic
electroluminescent display panel, the sheet resistance obtained by
combining the common electrode (CD) with the auxiliary wiring (SUP)
can be reduced to 10 .OMEGA./.quadrature. or less.
[0082] As a result, voltage drop due to the wiring resistance of
the auxiliary wiring (SUP) can be reduced more than in the past,
which contributes to the manufacture of a high-performance organic
electroluminescent display panel. In addition, it becomes possible
to easily cope with an increase in the size of a top emission type
organic electroluminescent display panel (for example, organic
electroluminescent display panel of 17 inches or more).
[0083] The metal wiring (MLINE) is an opaque metal film, for which
a metal material such as copper (Cu) or stainless steel (SUS) can
be used in addition to aluminum (Al). A blackening treatment may be
applied to the surface of the metal wiring (MLINE). In this case,
the visible characteristics of an organic electroluminescent
display panel can be improved.
[0084] As the resin film (RESIN), TAC (triacetylcellulose), POC
(polyolefin copolymer) or the like can be applied in addition to
PET. Other material can also be used as long as a film has a low
birefringence like those of the above resins.
[0085] In the above description, the auxiliary wiring constituting
member is manufactured by preparing a member previously obtained by
bonding a metal foil and a resin film together, patterning the
prepared member by photoresist, and removing a portion other than
the wiring by an etching method. However, similar effect can be
obtained also by using a deposition method or a printing
method.
[0086] In the embodiment, the auxiliary wiring constituting member
shown in FIGS. 5 and 6 and the organic electroluminescent display
panel not formed with the auxiliary wiring (SUP) in the structure
shown in FIG. 2 are respectively separately manufactured.
[0087] Thereafter, the resin film (RESIN) is bonded on the organic
electroluminescent display panel not formed with the auxiliary
wiring (SUP) in the structure shown in FIG. 2 by pressure bonding,
for example, by vacuum lamination such that the metal wiring
(MLINE) is not overlaid with the light emitting region (ARA).
[0088] In this case, since the deposited layer of the organic
electroluminescent display panel is a thin film and mainly includes
an organic layer, the elasticity of the deposited layer is higher
than that of the metal wiring (MLINE) of the resin film (RESIN).
Therefore, the metal wiring (MLINE) of the resin film (RESIN) bites
into the common electrode (CD) of the organic electroluminescent
display panel.
[0089] FIG. 7 shows a state before bonding the auxiliary wiring
constituting member shown in FIGS. 5 and 6 with the organic
electroluminescent display panel not formed with the auxiliary
wiring (SUP) in the structure shown in FIG. 2 while FIG. 8 shows a
state after bonding the auxiliary wiring constituting member shown
in FIGS. 5 and 6 with the organic electroluminescent display panel
not formed with the auxiliary wiring (SUP) in the structure shown
in FIG. 2.
[0090] As shown in FIG. 8, after bonding the auxiliary wiring
constituting member shown in FIGS. 5 and 6 with the organic
electroluminescent display panel not formed with the auxiliary
wiring (SUP) in the structure shown in FIG. 2, a usual sealing
process of an organic electroluminescent display panel is
performed, whereby an organic electroluminescent display panel is
completed.
[0091] In FIGS. 7 and 8, the structure between the substrate (SUB)
and the pixel electrode (AD) shown in FIG. 2 is represented by
BTFT, and the illustration of the structure between the substrate
(SUB) and the pixel electrode (AD) shown in FIG. 2 is omitted.
[0092] According to the embodiment, the following operation and
advantages can be obtained.
[0093] (1) The process of elevating a substrate temperature at the
time of film deposition of the auxiliary wiring (SUP) is no more
required, whereby it is possible to prevent the damage to the
organic electroluminescent element (OLE) at the time of forming the
auxiliary wiring (SUP).
[0094] (2) Owing to the process of bonding the resin film (RESIN)
formed with the metal wiring (MLINE) with high accuracy with an
organic electroluminescent display panel, the auxiliary wiring
(SUP) can be formed to the organic electroluminescent display panel
with the accuracy of alignment process, enabling the improvement in
the forming accuracy of the auxiliary wiring (SUP), that is, the
suppression of displacement of the auxiliary wiring (SUP).
[0095] (3) Applying a blackening treatment to the metal wiring
(MLINE) blackens the surface of the auxiliary wiring (SUP) to
suppress optical reflectivity, whereby it is possible to improve
black level when light is not emitted like in the case of BM (black
matrix) in a CRT and improve the contrast.
[0096] (4) The resin film (RESIN) formed with the metal wiring
(MLINE) with high accuracy has an electromagnetic wave absorption
effect as it is, whereby it is possible to suppress unnecessary
radiation (electromagnetic wave).
[0097] (5) The process of vapor depositing the metal wiring
(MLINE), a vacuum apparatus or photo process is no more required,
and an easy process, like the bonding of a color filter in a liquid
crystal display, is only required, whereby it is possible to
provide an effect of reducing the number of processes as well as to
reduce the cost due to the improvement in yield.
[0098] As described above, according to the embodiment, it is
possible to form the auxiliary wiring (SUP) with high accuracy
without damaging the organic electroluminescent element (OLE),
whereby it is possible to improve the performance and production
yield of a top emission type organic electroluminescent display
panel.
[0099] Although the invention made by the present inventor has been
described specifically based on the embodiment, the invention is
not limited to the embodiment. It is apparent that the invention
can be variously modified within the range not departing from the
gist of the invention.
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